Check valve for M38 vent system & cold weather primer

evanso1975 · Post by **evanso1975** » Wed Feb 13, 2013 11:16 am

I picked a couple of these up on Fleabay a few weeks ago:

While not an exact match, I believe they'll be a good substitute for the check valve that goes on the M38 fuel line up to the cold weather primer (and the vent line from the fuel pump to the bell housing on the "late" M38 engines).

The connections are 1/8" NPT female & 1/8" NPT male; due to the orientation of the valve, I'll need to use a couple of 1/8" NPT nipples & unions to connect in to my vent/primer system.

Note there's no spring inside this valve; it may be wise to fit one into the valve that connects to the fuel pump. The primer valve sits vertical, so should be fine without a spring. Here's the vendor details:

http://www.ebay.com/itm/Hit-Miss-Gas-En ... 6005565%26

Owen.

Post by **wesk** » Wed Feb 13, 2013 11:33 am

One of our Canadian members sold these for a few years. Remi.
http://www.willysmjeeps.com/v2/modules. ... heck+valve

The check valve is inserted in the "T" labeled in blue.

It is shown as a "Connector" and is screwed into the 90 deg elbow coming out of the center of the fuel pump.

Hawkshadow · Post by **Hawkshadow** » Wed Feb 13, 2013 4:42 pm

I'm trying very hard to picture where these would go, but I'm coming up short... Could one of you be so kind as to point me in the right direction?

Thanks in advance

evanso1975 · Post by **evanso1975** » Thu Feb 14, 2013 1:10 am

I'm trying very hard to picture where these would go, but I'm coming up short... Could one of you be so kind as to point me in the right direction?

Check out this page:

http://www.cj3a.info/sibling/m38vent/vent3.htm

Towards the bottom of the page, it shows a special fitting coming out of the fuel pump (last photo but one). Note that the "early" M38 (pre-engine no. 74419, according to that website) does not have this set-up.

The second valve is for the cold weather primer. The fuel line that links the fuel pump to the tank has a shut-off valve, with a brass tee connected to the front of it. If you have the cold weather primer system installed, the valve goes in the top of this tee. It's item "V" on Page 64 of the M38 ORD 9. If you don't have the cold weather primer, then the tee gets plugged (i.e. no valve).

Not sure if the M38CDN had the vent system or the cold weather primer though. The Canadian parts & maintenance manuals should tell you.

Owen.

Hawkshadow · Post by **Hawkshadow** » Thu Feb 14, 2013 11:17 pm

Please forgive me for a quick thread hijack. Referring to that vent line, my fuel pump appears to have that capped… was that standard in any instance?

Post by **wesk** » Thu Feb 14, 2013 11:33 pm

That is not a cap in the sense of a closed plug. That is the same one way vent fitting (ORD # 5196397 or Spicer # 16979) that is used in the differentials. When the "Under water vent system" was removed that was used to keep the crankcase vent port of the pump open but still keep any trash out of the pump. In the case of the M38A1 after MD23359 in 1953 Willys discontinued the "Under water vent system" plumbing and that fitting was used instead. (it can be seen in fig 67 on page 155 of TM 9-8014.

Early M38's up through MC53262 (Feb 52) did not use that port on the pump and it came with a square head 1/8" pipe plug.

Hawkshadow · Post by **Hawkshadow** » Sat Feb 16, 2013 12:05 am

Thank you once again gentlemen for sharing some of your wealth of knowledge!